[Premium-Rx] lamp replacement

[Terry O'Laughlin]

I have two printed circuit boards left over from when I was replacing the 
incandescent lamps in Racal 6790s.  I laid them out from the drawings in 
the Racal manual and they mimic the original LED boards as close as 
possible.  They are uncut rectangles and will need to be trimmed and have 
the holes cut out where the LCDs peek through.  The LEDs are in series 
blocks of four with dropping resistors.  I found a block of four LEDs was 
the optimal point for the incandescent supply voltage and keeping the 
dropping resistors small and low wattage.  There are provisions for 32 LEDs 
in all, 8 above and below each LCD window.

I'm not into Racals anymore.  The boards are available, one for $7 each 
postpaid or $10 for the pair postpaid.  These are just the printed circuit 
boards.  No LEDs or dropping resistors.

Best,
Terry O'
WB9GVB
http://watkins-johnson.terryo.org